Calling device



Sept. 18 1923. 1A595 w. L. WHIDDEN CALLING DEVICE Filed April '7, 1921' Meir/far I44 L. WH/DDE/V Patented Sept. 18, 1 923. i

teases TUWILLIAM L. wnrnnrn or srancKaLs, CALIFORNIA.

CALLING DEVICE.

To all "to/tom it may concern:

Be'it known that LWVILLIA L. Wnnr.

' DEN, a citizen of the United States, and resident of Spreckels, county of Monterey, and State of California, have invented a new and useful Calling Device, of which the following is a specification.

The present invention relates to improvements in calling devices for telephone exchanges and is designed principally for small telephone exchanges, such as private branch exchanges or the 40 drop camp boards used by the U. S. Government. At the present time the telephone companies and the U. S. Government use for these small exchanges a combination ringing and listening, key and for calling the subscribers they use either a generator or batteries including from 6 to 12 cells on the vibrator and from 48 to cells on the ringing or calling circuit. The object of my invention is to substitute for the dry batteries used for ringing or calling an induction coil, utilizing its alternating high-voltage current for ringing the bell, thereby saving the 48 to 60 batteries above mentioned.

I attain these objects bymeans of the mechanism illustrated in the accompanying drawing, in which Figure 1 represents a diagrammatic view of an nduction 0011 used in my combination and Figure 2 a side view of a combination ringing and listen- 'does not differ in any way from the 'ordinary induction coil, that is, the primary current flows from the battery through the metal plate 11, the contact screw 12, the spring 14, the primary winding on the coil and back tothe battery, thereby magnetizing the core, which attracts the armature 16, to which the spring 14, is attached. The swinging of the armature 16 toward the soft iron core breaks the contact between the contact screw 12 and the spring 14, thereby interrupting the current. The core becomes demagnetized and allows the armature to swing back to its original position so that the contactbetween the spring Application and April 7, 1921. Serial No. 459,239.

14 and the contact screw 12 is restored and a new current set up in the primary winding. In this manner the current flowing through the primary wire is alternately interrupted and restored and by these vibrations an alternating current of high voltage set up in the secondary wire. This alternating current I use in my device for ringing the bell 35 of the subscriber to be called.

As will beseen from the drawing, the listening and ringing key 21 of the type above mentioned is used in my wiring system with some modification; This key is a combination ringing and listening key, but only the ringing part of it is of interest in the present description. The key itself consists principally of a U-shaped frame (22) in the central member (23) of which alever (24) pivots, supporting on a pin (26) below its pivot a hard rubber rotary disk (27). The latter is in operative con tact with a leaf spring (28). It will be seen that when the lever is swung on its pivot it will force the spring in metallic contact with another spring (29). This contact closes in my combination the secondary circuit. But it will be seen that in the key illustrated another set of springs (31) and (32) which are special feature of my invention and are not at present found in the key is provided in close proximity to the first mentioned set of springs. The spring (31) carries near its upper end a small cylindrical body (33) of insulating material, which extends through a hole in the spring (29) to the spring (28). Thus the spring (28) in being forced to contact with the spring (29) also presses the spring (31) into metallic contact with the spring (32) and thereby closes the circuit containing the battery and the primary winding.

In this manner it will be seen that when the operator on the switch board, after having ascertained the number of the party wanted at the telephone and having connected the subscriber to be called, presses the lever so as to contact the springs (28) and (29) and the springs (31) and (32) both the primary and the secondary circuits of my induction coil will be closedand the current will flow from the battery through the contact (31) and (32) and the vibrator into the primary winding of the induction coil and back to the battery, while the alter nating, high voltage current set up in the secondary Wire will siniult-aneou sly flow throughtheieontact (28) wand ('29-) =t0 the bell 35 in t1i-e subscribers telepho'ne.

I claim In w switchboard, in combinetion, v a

calling "device comprising an 'intluct'ion cdil having a battery ancla vibrator ir uci'rcuit Wlth-itS p'nmaryevmdmg, and a call bell in circuit with its seeon'tlmay winding, and a ringlngland listening key including a U shaped'fraine; a lever pivotally 'supp'ortetl 1n the base ot thesamehaving-e rdlleref'insulitlllllg inateiizilesse c'iatetlwith one end, two

r'lea f springs included "in the seconclary circuit mounted in'the frame infspaeecl and parallel relation :to its-{center l1ie,'-e r eeX-' tending: 1nt-e. .operat1ve :PIOXlIHllZY to jthe,

tiiet'ed Whereby the secondary circuit is :closecl, 1a sec-0nd pair of leaf sprlngs associated with the primary circuit mounted in trolley-end aclaptecl to be forced in Contact" .With..theyotheruspr r gwhen the lever is ae- I 

